[PATCH v13 03/18] kunit: test: add string_stream a std::stream like string builder

[Stephen Boyd]

Quoting Brendan Higgins (2019-08-13 22:50:53)
> A number of test features need to do pretty complicated string printing
> where it may not be possible to rely on a single preallocated string
> with parameters.
> 
> So provide a library for constructing the string as you go similar to
> C++'s std::string. string_stream is really just a string builder,
> nothing more.
> 
> Signed-off-by: Brendan Higgins <brendanhiggins at google.com>
> Reviewed-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> Reviewed-by: Logan Gunthorpe <logang at deltatee.com>
> ---

Reviewed-by: Stephen Boyd <swboyd at chromium.org>

The spinlocks will probably need to change to be irqsaves in the future,
but I guess we can cross that bridge when we come to it.